An image processing application may be used to edit various characteristics of a digital image. For example, it may be the case that a particular region within an image is to have its contrast, luminosity, or other characteristic edited. To this end, a user may trace an object boundary shown in the image in order to select the region for editing. However, tracing the region may be slow, tedious, and subject to error. Thus, there exists a desire to facilitate the selection of an object boundary shown in an image.